Compilare: user.cpp: In function ‘int dfs(int)’: user.cpp:13:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[node].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:30:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nustiu.in", "rt", stdin); ^ user.cpp:31:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nustiu.out", "wt", stdout); ^ user.cpp:32:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &T); ^ user.cpp:34:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:39:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &u, &v); ^